Myocardial Infarction - Johnston

Question 1

Inverted T waves

Where usually?

Answer 1

Ischemia

- Chest leads (closest to ventricles)

Question 2

Causes of MI (occlusion)

Answer 2

• Atherosclerosis
• Vasospasm
• Vasculitis
• Dissection
• Genetics

Question 3

Chest pain, etc. not relieved by nitro or rest…Think what?

Answer 3

MI

Question 4

Silent MI…think what?

Answer 4

Diabetics, elderly women

Question 5

4 signs of new heart failure

Answer 5

• S3 gallop
• Crackles in lungs
• Increased JVD
• New murmur

Question 6

Autonomic responses for…

Anterior MI vs. Inferior MI

Answer 6

Anterior - sympathetic (tachy, HTN)

Inferior - parasympathetic (bradycardia, hypotension)

Question 7

EKG signs of STEMI

Answer 7

• Men - > 2mm STE (V2-V3)
• Women - > 1.5mm STE (2 or more contiguous leads)
• Maybe new LBBB

Question 8

NSTEMI or NST ACS - EKG

Answer 8

ST depression, T wave inversion

Question 9

Distinguishing NSTEMI from NSTE ACS

Answer 9

NSTEMI - elevated cardiac enzymes
NSTE ACS (angina) - normal cardiac enzymes

Question 10

Early phase of STEMI - EKG

What are they?

Answer 10

Tall hyperacute T waves

- Upward, slightly curved pattern

Question 11

Causes of inverted T waves (7)

Answer 11

• Normal in children (V1-3)
• Myocardial ischemia
• BBB
• Ventricular hyper. w/ strain
• P.E.
• Hypertrophic cardiomy.
• Raised ICP

Question 12

How to tell where the acute MI is occurring?

Answer 12

Where are the inverted T waves?

• Inferior = 2, 3, F
• Lateral = 1, L, V5-6
• Anterior = V2-6

Question 13

ANY T-wave inversion in leads _____ is considered pathological

Answer 13

V2-V6

Question 14

Other causes of STE?

Answer 14

• Pericarditis
• LVH w/ J point elevation
• Normal variant early repol.

Question 15

Pericarditis - EKG

Answer 15

ST segment elevation, usually flat or slightly concave, with potentially the whole T wave elevated to the next P wave

Question 16

Causes of ST depression?

Answer 16

• Subendocardial ischemia
• Stress test
• Digitalis toxicity

Question 17

Diagnostic feature for infarction on EKG

Answer 17

Significant Q waves (NECROSIS) in the infarcted area leads

Question 18

What is a “significant” Q wave?

Answer 18

> 1mm wide or 1/3 the QRS amplitude tall

Question 19

A normal Q wave in leads ___ is INSIGNIFICANT

Answer 19

AVR, V5-6

Question 20

SO, 3 things to look for when suspecting MI?

Answer 20

• Significant Q waves
• STE or ST depression
• Inverted T waves

Question 21

Describe why a Q wave means necrosis?

Answer 21

If the cardiac tissue under the lead is necrotic, there is no electrical activity, so the lead picks up the septal impulse moving away towards the other ventricle

Question 22

ST elevation in terms of MI means what?

Answer 22

ACUTE

Question 23

How to detect an acute posterior infarction?

Answer 23

The OPPOSITE is true of that in an ANTERIOR MI…

 - in V1-2, QRS is "flipped"
 - in V1-2, R wave is up
 - "STE" --> ST depression

Question 24

Significant Q in 1 and AVL

Answer 24

Lateral MI

Question 25

Significant Q in V1-V4

Answer 25

Anterior MI

Question 26

Significant Q in 2, 3, F

Answer 26

Inferior MI

Question 27

Large R in V1, V2 | Mirror test

Answer 27

Posterior MI

Question 28

Signs of MI can be obscured by ____

Answer 28

LBBB

Question 29

Persistent ST elevation (over 2 weeks)

Answer 29

Ventricular aneurysm (after an MI)

Question 30

Standard care for STEMI

Answer 30

- EKG and continuous cardiac monitoring - IVs inserted - Cardiac enzymes, blood panels, clotting times - Reperfusion, fibrinolysis - Heparin, MONA

Question 31

How to monitor reperfusion therapy?

Answer 31

Must see resolving ST elevation within 1-2 hours

Question 32

Major risk factor for fibrinolytic therapy

Answer 32

Intracranial hemorrhage

Question 33

Good times to use fibrinolysis

Answer 33

STEMI or new LBBB (within 12 hours)

Question 34

When to use a beta blocker in heart failure or MI?

Answer 34

If BP or HR are elevated due to compensatory response

Question 35

When to use an ACEI in HF or MI?

Answer 35

If EF is low or BP is high

Question 36

Previous Hx of MI, now hurts to breathe and feels better leaning forward Treatment?

Answer 36

Dressler syndrome (immune-mediated) Aspirin, NSAID

Question 37

Previous MI --> fibrinolytic therapy --> ventricular tachycardia

Answer 37

Accelerated idioventricular rhythm (AIVR)

Question 38

Arrhythmias associated w/ inferior MI

Answer 38

Sinus bradycardia, Wenckebach AV block

Question 39

Differential diagnosis for a STEMI

Answer 39

- Pericarditis - Myocarditis - Takotsubo (stress-induced) syndrome - Early repolarization

Question 40

Initial pharma treatments for STEMI

Answer 40

- Aspirin (unless contraindicated) | - IV Heparin or antiplatelet agent

Question 41

Full pharma list of treatments for STEMI

Answer 41

- Nitro - Oxygen - Morphine - Aspirin - BB - IF high BP or high HR - Stool softener - ACEI - IF low EF or high BP - Thrombolytic therapy

Question 42

Most common rhythm disturbances after an MI

Answer 42

V tach | V fib

Question 43

What can occur on EKG after fibrinolytic therapy? Serious?

Answer 43

Slow V tach (60-100) | Benign

Question 44

Most common cause of death after MI

Answer 44

Heart failure